Crystal and molecular structures of two polymorphs of 2,2-di(p-nitrophenyl)-1-picrylhydrazine dichloromethane, C18H11N7O10•CH2Cl2

1991 ◽  
Vol 69 (8) ◽  
pp. 1306-1314 ◽  
Author(s):  
Hong Wang ◽  
Richard J. Barton ◽  
Beverly E. Robertson ◽  
John A. Weil ◽  
Keith C. Brown
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Solvent Molecule ◽  
Molecular Structures ◽  
The Other ◽  
Dichloromethane Solution ◽  
Crystal Forms ◽  
Strong Resonance ◽  
Crystal And Molecular Structures ◽  
The Difference

Two polymorphic crystal forms (yellow and orange) of 2,2-di(p-nitrophenyl)-1-picrylhydrazine were crystallized from the same dichloromethane solution, and their crystal structures determined. The yellow form is triclinic, P1, a = 9.055(3), b = 10.396(4), c = 13.3187(3) Å, α = 89.83(2), β = 79.89(3), γ = 70.83(3)° at 228 K; R = 0.060, and Rw = 0.057 for 3511 reflections with I > 2σI. The orange form is monoclinic, P21/c, a = 8.999(3), b = 25.041(11), c = 12.207(5) Å, β = 121.66(2)° at 223 K; R = 0.053, and Rw = 0.058 for 3651 reflections with I > 2σI. The molecular structures in the two crystal forms are very similar. Both forms contain one solvent molecule per molecule of 2,2-di(p-nitrophenyl)-1-picrylhydrazine. In each, the two hydrazine nitrogen atoms have strong resonance interactions with the vicinal aromatic groups and both are sp2 hybridized. The molecular structure around the N—N linkage shows a staggered conformation. Thus the resonance interaction between the picryl group and the other two p-nitrophenyl groups is negligible. The difference in color between the two crystal forms is attributed to a difference in molecular packing. Key words: crystal structure, polymorphism, picrylhydrazine, conformation.

Structural diversity in the mercury(II) bis(N,N-dialkyldithiocarbamate) compounds: an example of the importance of considering crystal structure when rationalising molecular structure

1999 ◽  
Vol 214 (9) ◽  
Author(s):  
M. J. Cox ◽  
E. R. T. Tiekink
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
General Formula ◽  
Structural Diversity ◽  
Molecular Structures ◽  
Crystal And Molecular Structures ◽  
Layer Structures

AbstractThe crystal and molecular structures of four compounds of the general formula Hg(SThus, when there are no steric restrictions precluding association in the lattice, Hg–S interactions are present that give rise to dimeric structures or 2-dimensional layer structures in the case when R = H.

(3-Acetylpyridine-κN)chlorobis(triphenylphosphine-κP)copper(I): a suitable candidate for absolute asymmetric synthesis?

2006 ◽  
Vol 62 (7) ◽  
pp. m1569-m1571
Author(s):  
Anders Lennartson ◽  
Kent Salo ◽  
Mikael Håkansson
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Title Compound ◽  
The Other ◽  
Nucleophilic Attack ◽  
Suitable Candidate ◽  
Π Interactions ◽  
Crystallization Conditions ◽  
Chiral Crystals ◽  
Triphenylphosphine Ligand

It was found that 3-acetylpyridine is capable of displacing triphenylphosphine from [CuCl(PPh3)3], forming the title compound, [CuCl(C7H7NO)(C18H15P)2]. The two triphenylphosphine ligands possess the same sense of chirality, and the molecules are therefore conformationally chiral. The compound was found to crystallize as a racemate (centrosymmetric space group) under the crystallization conditions employed. The molecular structure shows that the carbonyl C atom is blocked at one side by a triphenylphosphine ligand, while the other face is open for nucleophilic attack. Obtaining chiral crystals of the title compound is thus a future objective. In the crystal structure, C—H...O(=C)-bonded dimers are formed, which are further stabilized by π–π interactions. The dimers form infinite chains through weak C—H...π interactions.

Synthesis and Characterization of Some Functional Luminol Derivatives with Aromatic Substituted Groups

2011 ◽  
Vol 197-198 ◽  
pp. 606-609 ◽  
Author(s):  
Ti Feng Jiao ◽  
Yuan Yuan Xing ◽  
Jing Xin Zhou ◽  
Wei Wang
Keyword(s):  
Molecular Structure ◽  
Thermal Stability ◽  
Molecular Structures ◽  
Synthesis And Characterization ◽  
Functional Material ◽  
Aromatic Substituent ◽  
The Difference ◽  
Imide Group ◽  
Thermal Stability Of

Some functional luminol derivatives with aromatic substituted groups have been designed and synthesized from the reaction of the corresponding aromatic acyl chloride precursors with luminol. It has been found that depending on the size of aromatic groups, the formed luminol derivatives showed different properties, indicating distinct regulation of molecular skeletons. UV and IR data confirmed commonly the formation of imide group as well as aromatic segment in molecular structures. Thermal analysis showed that the thermal stability of luminol derivatives with p-phthaloyl segment was the highest in those derivatives. The difference of thermal stability is mainly attributed to the formation of imide group and aromatic substituent groups in molecular structure. The present results have demonstrated that the special properties of luminol derivatives can be turned by modifying molecular structures of objective compounds with proper substituted groups, which show potential application in functional material field and ECL sensor.

Optical Property and Photoisomerization of Some Functional Azobenzene Derivatives with Aromatic Substituted Groups

2011 ◽  
Vol 121-126 ◽  
pp. 1009-1013
Author(s):  
Ti Feng Jiao ◽  
Xu Hui Li ◽  
Qiu Rong Li ◽  
Jing Xin Zhou
Keyword(s):  
Molecular Structure ◽  
Optical Property ◽  
Potential Application ◽  
Uv Light ◽  
Molecular Structures ◽  
Functional Material ◽  
Methyl Group ◽  
Uv Light Irradiation ◽  
The Difference ◽  
Azobenzene Derivatives

Some functional azobenzene derivatives with aromatic substituted groups have been synthesized and their photoisomerization have also been investigated. It has been found that depending on different substituted groups, such as phenyl or naphthyl segments, the formed azobenzene derivatives showed different properties, indicating distinct regulation of molecular skeletons. Spectral data confirmed commonly the characteristic absorption of substituted groups and aromatic segments in molecular structures. In addition, the photoisomerization of all compounds in solution can show trans-to-cis photoisomerization by UV light irradiation, and demonstrate distinct isomerization ratio depending on effect of different substituted headgroups. The difference is mainly attributed to the aromatic substituted headgroups and methyl group in molecular structure. The present results have showed that the special properties of azobenzene derivatives could be effectively turned by modifying molecular structures of objective compounds with proper substituted groups, which show potential application in sensor and functional material field.

Untersuchungen an Stickstoff-Brom-Verbindungen, IV / Studies on Nitrogen-Bromine Compounds, IV

1977 ◽  
Vol 32 (12) ◽  
pp. 1416-1420 ◽  
Author(s):  
Omar Jabay ◽  
Hans Pritzkow ◽  
Jochen Jander
Keyword(s):  
Crystal Structure ◽  
Nitrogen Atom ◽  
Structure Analysis ◽  
Electron Acceptors ◽  
Molecular Structures ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Solid Nitrogen ◽  
Intermolecular Contacts

The crystal and molecular structures of N-bromobenzamide (NBB), N-bromosuccinimide (NBS), and N,N-dibromobenzenesulfonamide (NBBS) were determined by X-ray structure analysis. The nitrogen atoms in NBB and NBS have a trigonal planar coordination (sp2) and the N—Br distances lie in the same range (1.82 A, 1.84 A). The N—Br distance in NBBS, where the nitrogen atom is sp3-hybridized, is somewhat longer (1.88 A). In these structures the molecules are connected by O···H—N (NBB), O···Br—N (NBS) or N···Br—N (NBBS) intermolecular bonds forming endless chains; positivated hydrogen atoms or, in case that they are absent, positivated bromine atoms act as electron acceptors with oxygen or sp3- hybridized nitrogen atoms. These results suggest, that in solid nitrogen tribromide, the crystal structure of which cannot be determined, the nitrogen atoms will be sp3-hybridized and intermolecular contacts via N—Br···N will occur.

scholarly journals Preparation and Crystal Structure of a Platinum(II) Complex of [CH2N(CH2COOH)CH2CONH2]2, the Hydrolysis Product of an Anti-Tumour Bis(3,5-Dioxopiperazin-1-YL)Alkane

1994 ◽  
Vol 1 (4) ◽  
pp. 321-328 ◽  
Author(s):  
Kevin B. Nolan ◽  
Leo P. Ryan ◽  
Colm J. Campbell ◽  
Patrick McArdle ◽  
Desmond Cunningham ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Hydrolysis Product ◽  
Molecular Structures ◽  
3 Dimensional ◽  
Crystal And Molecular Structures ◽  
Dimensional Network ◽  
Square Planar ◽  
Ligand Bond ◽  
Hydrogen Bonded

The synthesis and crystal and molecular structures of the platinum(II) complex Pt(HL)Cl where H2L is the diacid diamide –[CH2N(CH2COOH)CH2CONH2]2, a hydrolytic metabolite of an antitumour active bis(3,5-dioxopiperazin-1-yl)alkane are reported. The complex is square planar and contains HL− as a tridentate 2N (amino), O (carboxylate) donor. The metal to ligand bond distances are Pt-Cl 2.287(1) Å, Pt-O 2.002 (1) Å, Pt-Ntrans Cl 2.014(1) Å and Pt-Ntrans O 2.073 Å. There is extensive hydrogen bonding, each molecule of Pt(HL)Cl being intermolecularly hydrogen bonded to ten others giving a 3-dimensional network. There is also one intramolecular H-bond.

Purine complexes of platinum: synthesis, nmr, and crystal and molecular structures of cis-chloro(caffeine)bis(triethylphosphine)platinum(II) fluoroborate and cis-bis(isocaffeine)bis(triethylphosphine)platinum (II) fluoroborate

1983 ◽  
Vol 61 (6) ◽  
pp. 1132-1141 ◽  
Author(s):  
Gordon William Bushnell ◽  
Roderick James Densmore ◽  
Keith Roger Dixon ◽  
Arthur Charles Ralfs
Keyword(s):  
Crystal Structure ◽  
Nmr Spectra ◽  
Molecular Structures ◽  
Platinum Drugs ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Bond Lengths ◽  
Antitumour Agents ◽  
Crystal And Molecular Structures ◽  
Square Planar

Synthesis and 31P nmr spectra of the complex cations, cis-[PtCl(L)(PEt3)2]+, L= theophylline, caffeine, or isocaffeine, and cis[Pt(isocaff)2(PEt3)2]2+ are reported. The crystal structure of cis-[PtCl(caffeine)(PEt3)2][BF4] is determined, space group [Formula: see text], a = 1.1766(6), b = 1.4428(5), c = 0.9002(4) nm, α = 97.28(4)°, β = 97.69(4)°, γ = 100.96(5)°, Dm = 1.649 g cm−1, the bond lengths are Pt—Cl= 233.4(4) pm, Pt—N = 215(1) pm, Pt—P = 225.4(5) pm (mean), and the residual R = 0.071. The crystal structure of cis-[Pt(isocaffeine)2(PEt3)2][BF4]2 is orthorhombic, space group Pbca, a = 2.317(3), b = 1.717(3), c = 2.130(3) nm, Dm = 1.574 g cm−3, with an opposing isocaffeine conformation, bond lengths Pt—N = 211(2) pm, Pt—P = 227.6(9) pm (mean), and R = 0.073. Both crystal structures contain approximately square planar Pt(II) coordination with the purine coordinated via an imidazole nitrogen. The structures are discussed as models for the possible involvement of [Formula: see text] chelation of guanine to platinum when platinum drugs act as antitumour agents, but there is no evidence that isocaffeine acts as an [Formula: see text] chelate.

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